diff --git a/glib/tests/fileutils.c b/glib/tests/fileutils.c
index 40ecdd447..ebc62af14 100644
--- a/glib/tests/fileutils.c
+++ b/glib/tests/fileutils.c
@@ -254,7 +254,7 @@ test_build_filename (void)
 
   /* Test also using the slash as file name separator */
 #define U "/"
-/*  check_string (g_build_filename (NULL), "");*/
+  check_string (g_build_filename (NULL), "");
   check_string (g_build_filename (U, NULL), U);
   check_string (g_build_filename (U"x", NULL), U"x");
   check_string (g_build_filename ("x"U, NULL), "x"U);